Class DataProvider

Defined in File data_provider.hpp

Class Documentation

class DataProvider

Provider interface for entity data resources.

Typed provider interface for plugins that serve SOVD data resources (GET /{entity_type}/{id}/data, GET /{entity_type}/{id}/data/{name}). Unlike LogProvider/ScriptProvider (singletons), multiple DataProvider plugins can coexist - each handles its own set of entities.

Entity ownership is determined by IntrospectionProvider: entities created by a plugin’s introspect() are routed to that plugin’s DataProvider.

See also

OperationProvider for the operations counterpart

Thread safety: All methods may be called from multiple HTTP handler threads concurrently. Implementations must provide their own synchronization.

Public Functions

virtual ~DataProvider() = default

virtual tl::expected<dto::DataListResult, DataProviderErrorInfo> list_data(const std::string &entity_id) = 0

List available data resources for an entity.

Returns a typed DataListResult envelope around the plugin-defined response body. JsonWriter emits content verbatim, so the wire bytes are byte-identical to the pre-typed nlohmann::json ABI. The payload shape is plugin-determined (typically {"items": [...]} with per-item fields varying across backends - ROS topic metadata, OPC-UA node attributes, UDS DID descriptors, …). The OpenAPI schema is opaque (x-medkit-opaque:true).

Parameters:: entity_id – SOVD entity ID (e.g., “openbsw_demo_ecu”)

virtual tl::expected<dto::DataValue, DataProviderErrorInfo> read_data(const std::string &entity_id, const std::string &resource_name) = 0

Read a specific data resource.

Returns a typed DataValue envelope around the plugin-defined response body. JsonWriter emits content verbatim, so the wire bytes are byte-identical to the pre-typed nlohmann::json ABI. The payload shape is runtime-dependent (live ROS message, OPC-UA value with metadata, UDS DID payload, …) and the OpenAPI schema is opaque (x-medkit-opaque:true).

Parameters:

entity_id – SOVD entity ID
resource_name – Data resource name (e.g., “hardcoded_data”)

virtual tl::expected<dto::DataWriteResult, DataProviderErrorInfo> write_data(const std::string &entity_id, const std::string &resource_name, const nlohmann::json &value) = 0

Write a data resource value.

Returns a typed DataWriteResult envelope around the plugin-defined response body. JsonWriter emits content verbatim, so the wire bytes are byte-identical to the pre-typed nlohmann::json ABI. The payload shape is plugin-determined (typically {"status": "ok"} or similar) and the OpenAPI schema is opaque (x-medkit-opaque:true).

Parameters:

entity_id – SOVD entity ID
resource_name – Data resource name
value – JSON value to write